Giovanni Valente (Politecnico di Milano) will be visiting the Geneva Symmetry Group (GSG) this week. The GSG is happy to present two talks by him, a more formal talk on Wednesday, and an informal seminar on Thursday (abstracts below):
Wednesday, 8 May 2019, at 18:15 in Room L208 (Landolt):
Giovanni Valente (Politecnico di Milano): Spontaneous symmetry breaking and physical inequivalence: the case of quantum statistical mechanics
Thursday, 9 May 2019, at 16:15 in room B002 (Bastions):
Giovanni Valente (Politecnico di Milano): On the paradox of reversible processes in thermodynamics
Anyone who wishes to attend is welcome.
Wednesday, 8 May 2019 in Room L208 (Landolt) – Giovanni Valente (Politecnico di Milano): Spontaneous symmetry breaking and physical inequivalence: the case of quantum statistical mechanics
Abstract: In this talk I discuss an outstanding issue in philosophy of physics concerning the relation between quantum symmetries and the notion of physical equivalence. Specifically, I deal with a dilemma arising for quantum symmetry breaking that was posed by Baker (2011), who claimed that if two ground states are connected by a symmetry, even when it is broken, they must be physically equivalent. However, I argue that the dilemma is just apparent. In fact, I object to Baker’s conclusion by showing that the two thermodynamical phases of a ferromagnet, which are connected by the so-called flip-flop symmetry, are physically inequivalent, thereby providing a counter-example to his claim.
In terms of technical difficulty, this talk rates 4/5
Thursday, 9 May 2019 in Room B002 (Bastions) – Giovanni Valente (Politecnico di Milano): On the paradox of reversible processes in thermodynamics
Abstract: This paper discusses an argument by Norton (in: European Philosophy of
Science—Philosophy of Science in Europe and the Viennese Heritage, Vienna Circle
Institute Yearbook, vol 17, Springer, Dordrecht, pp 197–210, 2014, 2016) to the effect that reversible processes in thermodynamics have paradoxical character, due to the infinite-time limit. For Norton, one can “dispel the fog of paradox” by adopting a distinction between idealizations and approximations, which he himself puts forward. Accordingly, reversible processes ought to be regarded as approximations, rather than idealizations. Here, we critically assess his proposal. In doing so, we offer a resolution of his alleged paradox based on the original work by Tatiana Ehrenfest-Afanassjeva on the foundations of thermodynamics.
Relevant paper: Giovanni Valente (2019). On the paradox of reversible processes in thermodynamics. Synthese. 196: 1761-1781.